There is no de facto standard SVN client for OS X as TortoiseSVN is for the Windows operating system. However a good alternative to be used is the svnx client.
It provides lightweight interface, easy to use – except of the excessive separation into sub windows for working copies, repositories, etc.
The tool can be downloaded for free at http://www.lachoseinteractive.net/en/community/subversion/svnx/
OS X – SVN Client